Destroying an Instantiated Object Destroys All Clones of the Same Object,Destroying an instantiated object destroys all other clones of the same object

Basically, I'm trying to recreate a DDR kind of thing and I'm just trying to get the basic gameplay down. I'm still a novice when it comes to game dev but I have a little bit of experience. Right now I'm instantiating a random arrow of 4 different arrow directions, and when I do that I put it in a list. The first arrow of the list is always the next arrow in the scene, and I use RemoveAt() to ensure that. The problem I'm getting is that when I get two of the same arrow directions (coming from the same original prefab) in a row in the list, deleting one will delete all of them if they are consecutive. It only does it like this; for example, if my arrow order is left, left, down, it deletes both lefts. If my arrow order is left, down, left, it only deletes the first left and I just can't figure out why. I know it's not the names because I've tried changing that each time but that did nothing, I've tried using a queue, everything I do I just can't get it to work and I need help.